In the related art, an ultraviolet ray irradiation apparatus is widely used for fluorescence reaction observation, sterilization purposes in the field of medical care or biotechnology, electronic component adhesion, or curing of ultraviolet ray curable resin and ink. In particular, as a lamp light source of the ultraviolet ray irradiation apparatus used in curing the ultraviolet ray curable resin for use in adhering small components in the field of electronic components, the ultraviolet ray curable ink for use in the field of printing or the like, a high pressure mercury lamp, a metal halide lamp, or the like is used.
In recent years, there has been a strong worldwide demand for a reduced burden on the global environment. Therefore, an ultraviolet ray irradiation element which has relatively long durability and energy-saving performance, and which can suppress ozone generation has been actively employed in the lamp light source.
However, the ultraviolet ray irradiation element has relatively low intensity of illumination. Therefore, for example, as disclosed in Japanese Unexamined Patent Publication JP-A 2008-244165, a light irradiation apparatus is generally used which has a configuration where plural devices are mounted on a support by preparing a device in which plural light emitting elements are mounted on one substrate. In this manner, ultraviolet ray irradiation energy needed to cure the ultraviolet ray curable ink is obtained.
However, depending on the service environment of the ultraviolet ray irradiation apparatus, and types of the ultraviolet ray curable ink and a target (recording medium) for applying the ultraviolet ray curable ink, there is a problem in that it is difficult to increase adhesion between the ultraviolet ray curable ink and the target.
The invention is made in view of the above-described problem, and an object thereof is to provide a light irradiation apparatus and a printing apparatus which achieve increased adhesion between an ultraviolet ray curable ink and a target regardless of the service environment of an ultraviolet ray irradiation apparatus, and types of the ultraviolet ray curable ink and the target for applying the ultraviolet ray curable ink.